Problem Exists (Reverse DNS)

AndyX

Well-Known Member
Sep 25, 2015
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11
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Los Altos, CA
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Website Owner
Hello,

When I go to:

cPanel -> Email Deliverability

I see the following error message:

pic001.jpg

According to my web host:

This is an issue with how cPanel handles DNS Lookups within a virtualized environment.

cPanel is aware of the bug.
Is there a timeline as to when this bug will be fixed?

Thank you.
 

AndyX

Well-Known Member
Sep 25, 2015
73
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Los Altos, CA
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Website Owner
From my web host:

I was able to run the terminal command below as a work around for the time being. Now PTR is showing as valid in cPanel.

whmapi1 set_up_dns_resolver_workarounds

1591390757017.png
 

cPSamuelM

Technical Analyst Team Lead
Staff member
Nov 20, 2019
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Hello @AndyX

Thank you for contacting cPanel! I am glad to see that you were able to resolve the issue for the time being.

With the release of cPanel 84 we did replace the internal DNS resolver with Unbound: https://docs.cpanel.net/release-notes/84-release-notes/#replace-dns-resolver

With the introduction of Unbound, we became aware of some issues that we actively worked to address, but I am not aware of any issues related to PTR (reverse DNS) lookups in virtualized environments. You might be able to find more details about the specific error by using the following command:


grep -i unbound /usr/local/cpanel/logs/error_log


Although, now that you have resolved the issue, it may be difficult to trigger the error and correlate the log file entries to a specific action.
 

AndyX

Well-Known Member
Sep 25, 2015
73
11
58
Los Altos, CA
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Website Owner
Hi cPSamuel,

I just check and the original issue (post #1) is happening again. So the terminal command executed in post #2 is only a temporary fix and only for a few hours.
 
Last edited:

cPSamuelM

Technical Analyst Team Lead
Staff member
Nov 20, 2019
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Hello again @AndyX

Thanks for getting back to us. It does appear that this issue may be related to or internal case CPANEL-30992. There is no known workaround to address the issue manually, however our developers are actively working to include a patch for this issue in an upcoming version of cPanel. Once this is included in an update, you will see a note regarding CPANEL-30992 in our changelogs at https://go.cpanel.net/changelogs.

I have removed the screenshot from your most recent post to ensure that your server's IP address is not exposed publicly.

Best regards
 
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cPanelLauren

Product Owner
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Nov 14, 2017
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Based on the implications not timing out can cause with the lookups this case was actually flagged as won't fix. It looks like our development team may be looking for other options but there is no further update at this time.
 

AndyX

Well-Known Member
Sep 25, 2015
73
11
58
Los Altos, CA
cPanel Access Level
Website Owner
Hi Lauren,

The issue I reported in post #1 of this thread still exists, yet if I click Manage there are no errors shown, Reverse DNS (PTR) shows Valid. Would increasing the Email deliverability status function time-out solve the issue?
 

cPanelChris

Moderator
Staff member
Feb 16, 2020
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Houston, TX
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Hello @AndyX ,

It possible this may help. The Unbound rDNS timeout issues can be intermittent, so you may or may not see issues reported. This could explain why the error is occurring in one area of the interface and not another. Given that, increasing the Email deliverability status function timeout may not help as the error may still be a function of the Unbound PTR check timing out.
 

cPanelChris

Moderator
Staff member
Feb 16, 2020
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Houston, TX
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Hello @AndyX ,

Email Deliverability can be disabled in the Feature Manager in WHM. "Email Deliverability (Authentication)" is the option that controls this feature.
 

AndyX

Well-Known Member
Sep 25, 2015
73
11
58
Los Altos, CA
cPanel Access Level
Website Owner
Hi Chris,

Sorry I was not clear. The Email Deliverability is a wonderful cPanel function and no way would I want to disable it. I suggested you remove the "Email Deliverability Status" column as it really is not needed and vague in it's function. Users would need to click "MANAGE" to verify DKIM, SPF and Reverse DNS (PTR) are valid.

In the MANAGE page, when Reverse DNS (PTR) sows errors, I can simply reload the page a few times and it will show valid. It appears the issue is strictly a timeout issue, please increase the timeout to eliminate the issue.
 

cPanelChris

Moderator
Staff member
Feb 16, 2020
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Houston, TX
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Hello @AndyX ,

Looking into this further, I did find there is an internal case (CPANEL-33302) for this which is patched in 11.92. The patch will be backported to 11.90 and 11.86 as well.
 

cPanelChris

Moderator
Staff member
Feb 16, 2020
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Houston, TX
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Hello @AndyX ,

The current WHM/cPanel version of the server will be in the upper right corner of WHM. You can also see it in the following location of WHM, which will also allow you to choose the release tier.

Home » Server Configuration » Update Preferences

You can also view the changelogs from the following location in WHM. The changelogs will contain the cases that have been resolved.

Home » cPanel » Change Log